/* 
stdin
stdout
stderr
*/

#include  <stdio.h>

int main(int argc, char const *argv[])
{
	printf("please  input  the value a:\n");

	int  a;

	scanf("%d",&a);

	if(a<0){
	      printf("the value must >0\n");

	      return -1;
	}
	 printf("standland  input  output  error\n");

	 fprintf(stdout, "please  input  the value a:\n");
	 fscanf(stdin,"%d",&a);
	 if(a<0){
	      fprintf(stderr, "the value must >0\n");

	      return  1;
	}


	
	return 0;
}

